ML20135A268
| ML20135A268 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 02/19/1997 |
| From: | Duffy D VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BVY-97-25, NUDOCS 9702270077 | |
| Download: ML20135A268 (2) | |
Text
o VE'RMONT YANKEE NUCLEAR POWER CORPORATION J
Ferry Road, Brattleboro, VT 05301-7002 ENGINE I OFFICE 580 MAIN STREET BOLTON. MA 01740 (508)779 6711 i
February 19,1997 BVY 97-25 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washingtun, DC 20555
References:
(a) License No. DPR-28 (Docket No. 50-271)
(b) Letter, VYNPC to USNRC, BVY 96-43, dated April 4,1996 (c) Telecon, USNRC to VYNPC, dated February 12,1997
Subject:
Clarification Regarding Use of Vernon Tie for Appendix R Compliance in Reference (b), Vermont Yankee requested an exemption from 10CFR50, Appendix R, section Ill.L to allow use of the Vernon Tie as a source of ac power in alternative shutdown scenarios. Vermont Yankee utilizes alternative shutdown capability in the event of a fire in the control room or cable spreading room. Current /, Vermont Yankee uses one of the two onsite emergency diesel generators in an alternate shutdown mode as a source of ac power when offsite power is not available in the event of a control room or cable spreading room fire.
This exemption was requested to facilitate the restoration of ac power to safe shutdown equipment and to reduce the operator timeline for initiating alternate shutdown systems. Use of the Vernon Tie has several significant advantages over use of an emergency diesel generator to meet altemate shutdown requirements. These advantages include: prompt restoration of power using simpler operator actions; continuous operation without dependence on support systems; and reliability of the Vernon Tie. As stated in Reference (b), the Vernon Tie is normally energized and the availability of Vernon Station has historically been well above 99%,
exceeding the required alternate ac source availability of 95%. However, in the event the Vernon Tie is unavailable, a diesel generator will be available to provide backup power.
In Reference (b) Vermont Yankee stated that it would institute the following administrative limit in the event of an unplanned unavailability of the Vernon Tie:
Power operation may continue for no more than 15 days, unless the Vernon Tie is retumed to snvice or a Basis for Maintaining Operability (BMO) evaluation is written and approved.
f in Reference (c), the NRC ctaff expressed concern that the Vernon Tie, if approved for use as t
Vermont Yankee's preferred source of power for alternative shutdown, may be out of service h
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VERMONT YANKEE NUCLEAR POWER CORPORATION iT United States Nuclear Regulatory Commission l
February 19,1997 Fage 2 of 2 I
indefinitely without NRC notification. In consideration of the NRC staffs concern, Vermont Yankee will revise, upon approval of the exemption requested in Reference (b), the -
administrative limit stated above to require that a special report be submitted to the NRC in the 4
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. event of an unplanned unavailability of the Vernon Tie. The revised administrative limit will read:
5-Power operation may continue for no more than 15 days, unless the Vemon Tie is retumed to service or a Basis for Maintaining Operability (BMO) evaluation it, written and approved by the Plant Operations Review Committee.
if the Vemon Tie cannot be retumed to service within 15 days, submit a report to i
the NuclearRegulatory Commission, in accordance with 10CFR50.4, within the l
next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> outlining the reason for the unavailability, corrective actions being taken to restore the Vemon Tie, compensatory actions in place to provide ac power for Appendix R attemative shutdown fire scenarios and the time required -
i to make the Vemon Tie available.
We trust that this submittal provides the requested information. - However, should you have questions or require additional information, please contact this office.
l i
i Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION HW -
James J. Duffy Licensing Engineer i
c: USNRC Region i Administrator l
USNRC Project Manager-VYNPS USNRC Resident inspector-VYNPS
.